如何检查函数/方法采用哪些参数? [英] How to check which arguments a function/method takes?

问题描述

为了使我在 Python 中构建的几个模块保持一致，我想做一些自动代码检查.为此，我想检查模块的函数和函数采用的参数.我可以使用 hasattr() 来检查模块是否确实包含预期的功能.到目前为止一切顺利.

我现在想看看函数采用哪些参数.只需查看变量名称就足够了.我不知道我将如何能够做到这一点.有谁知道我如何获得函数所采用的参数的名称?

解决方案

您可以使用 inspect.getargspec() 以查看接受哪些参数，以及关键字参数的任何默认值.

演示:

<预><代码>>>>def foo(bar, baz, spam='eggs', **kw): 通过...>>>进口检验>>>检查.getargspec(foo)ArgSpec(args=['bar', 'baz', 'spam'], varargs=None, Keywords='kw', defaults=('eggs',))>>>检查.getargspec(foo).args['bar', 'baz', '垃圾邮件']

在 Python 3 中，您想使用 inspect.getfullargspec() 因为这个方法支持新的 Python 3 函数参数特性:

<预><代码>>>>def foo(bar: str, baz: list, spam: str = 'eggs', *, monty: str = 'python', **kw) ->无:通过...>>>进口检验>>>检查.getfullargspec(foo)FullArgSpec(args=['bar', 'baz', 'spam'], varargs=None, varkw='kw', defaults=('eggs',), kwonlyargs=['monty'], kwonlydefaults={'monty': 'python'}, annotations={'baz': , 'return': None, 'spam': , 'monty': , 'bar': })

inspect.getargspec() 在 Python 3 中应该被视为已弃用.

Python 3.4 添加了 inspect.Signature() 对象:

<预><代码>>>>检查签名(富)<inspect.Signature object at 0x100bda588>>>>str(inspect.signature(foo))"(bar:str, baz:list, spam:str='eggs', *, monty:str='python', **kw) -> 无">>>检查签名(foo).参数mappingproxy(OrderedDict([('bar', <0x100bd67c8 'bar'处的参数>), ('baz', <0x100bd6ea8 'baz'处的参数>), ('spam', <0x100bd69f8处的参数spam'>), ('monty', <参数在 0x100bd6c28 'monty'>), ('kw', <参数在 0x100bd6548 'kw'>)]))

以及更多有趣的签名选项.

To keep a couple modules I'm building in Python a bit consistent I want to do some automated code checking. For this I want to check the modules for their functions and the arguments the functions take. I can use hasattr() to check whether the module actually contains the expected functions. So far so good.

I now want to see which arguments the functions take. It would be enough to simply see the variable names. I have no idea how I would be able to do this though. Does anybody know how I can get the names of the arguments a function takes?

解决方案

You can use inspect.getargspec() to see what arguments are accepted, and any default values for keyword arguments.

Demo:

>>> def foo(bar, baz, spam='eggs', **kw): pass
... 
>>> import inspect
>>> inspect.getargspec(foo)
ArgSpec(args=['bar', 'baz', 'spam'], varargs=None, keywords='kw', defaults=('eggs',))
>>> inspect.getargspec(foo).args
['bar', 'baz', 'spam']

In Python 3, you want to use inspect.getfullargspec() as this method supports new Python 3 function argument features:

>>> def foo(bar: str, baz: list, spam: str = 'eggs', *, monty: str = 'python', **kw) -> None: pass
... 
>>> import inspect
>>> inspect.getfullargspec(foo)
FullArgSpec(args=['bar', 'baz', 'spam'], varargs=None, varkw='kw', defaults=('eggs',), kwonlyargs=['monty'], kwonlydefaults={'monty': 'python'}, annotations={'baz': <class 'list'>, 'return': None, 'spam': <class 'str'>, 'monty': <class 'str'>, 'bar': <class 'str'>})

inspect.getargspec() should be considered deprecated in Python 3.

Python 3.4 adds the inspect.Signature() object:

>>> inspect.signature(foo)
<inspect.Signature object at 0x100bda588>
>>> str(inspect.signature(foo))
"(bar:str, baz:list, spam:str='eggs', *, monty:str='python', **kw) -> None"
>>> inspect.signature(foo).parameters
mappingproxy(OrderedDict([('bar', <Parameter at 0x100bd67c8 'bar'>), ('baz', <Parameter at 0x100bd6ea8 'baz'>), ('spam', <Parameter at 0x100bd69f8 'spam'>), ('monty', <Parameter at 0x100bd6c28 'monty'>), ('kw', <Parameter at 0x100bd6548 'kw'>)]))

and many more interesting options to play with signatures.

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